Explosive compound



UNITED STATES PATENT -OFFICE.

THOM/AS VARNEY, QFOAKLAND, CALIFORNIA.

QEXPLO'SHIII-E COMPOUND.

SPECIFICATION forming part of Letters :PatBnfi'No. 249,701, dated November 15, 1881. Application filed August 11, 1881. (No specimens.)

To all whom it may concern;

Be it known that I, THoMAs VARNEY, of Oakland, county of Alameda and State of California, have made an Improvement in Explosive "Com pounds; and I hereby declare the following to be a full, clear, and exact description thereof. I

The invention relates to thatclass of explosives known as dyuamiteNo. 2-thatis, dy-

namite having a combustible or semiexplosive absorbent.

The object of .the invention is to produce a powder which will detonate 'with a low per cent. of nitro-glycerine, and therefore be cheap,

and at the same time increase the power do- To obtain the highest degree of explosive force-from the absorbentin this class of powders it is necessary to have itin a very fine state of division; but thevfiner'it is the more absorbent itls,

twenty. parts of nitro-glyceriu'e to eighty-five or'eighty off-absorbent are required. Therefore tomake-a powder capable of detonation with from three tosix per cent. of nitro-glycerine requires the absorbent to be very coarse; but this coarseness weakens the powder. My invention does away with the necessity of coarseness by givin g the absorbent a peculiar porosity, which facilitates detonation and the decomposition of the absorbent.

"The powder,which I call Varney Powder,

7 is prepared as follows: The materials of the absorbent are made fiue-'-the finer they are the stronger willbe the powder. These fine particles are then aggregated or collected into small assemblages. This is done bydlstributiug among them. evenly a certain proportion of some pulverized solid substance -capable ofbeiugsoftened or made pasty while in mixture,

whereby each soft particle will attach to itself all the solid particles in contact-with it, and,

when hardened will hold them in this contact and thereafter remain in the mixtnrein this a ggregated form. It is evident that the soft ma terial should itself be such as'to contribute to of making paste or becoming adhesive are suitand themore nitro-glycerinc it requires for detonation. Ordinarily fifteen or,

able,- ainlalso various glutinous substances,

and also soluble ones, such as the sugars, va=

rious gums, and the nitrates generally. Its proportion should be just enough to aggregate all, or substantially all, the solid particles, and

no more. Any excess beyond this tends to produce large and solid grains. A proportion either too small or too large is readily observable- Insome cases, and especially when the proportion of nitro-glycerine is to be liberal, a considerable proportion of fine particles are not seriously objectionable. 'In such cases any ingredient or part of one may be left out till the balance is aggregated, when-it can be added,

-or a less proportion of softening material may be used. The method of softening will de- 'pend on the character of the material to be softened. Sulphur, rosin, hard tar, &c., must be softenedby heat. When this is done in thin layers the mass need not'be stirred or disturbed while heating, but when in deep masses it should be stirred, so as to cause all parts to heat alike.

When flour, starch, &c., are used they mustbe softened-that is, made into a paste-by some liquid stirred evenly into the ,mass, and then dried out by aheat suflicient to make paste.

If soluble substances are used, such as sugar, gum, or niter, they may be mixed with the other ingredients, moistened and dried. When the hardening is accompanied by crystallization, as in the use of niter, the aggregation is of adifl'erent character, andnot as satisfactory in all respects.

In all cases where practicable it is better for the mass notto bedisturbed while thehardeniu g Jtakes place. When the hardening has taken place the mass will naturally be removed. This will disturb and draw apart the granules oraggregatio'ns, and the exterior particles of each granule from those of the oth ers, and produce a mass of aggregated particles instead of a mass of particles, thus substantially leaving each fine particle fully exposed to the explosive influence.

required before aggregating. It also gives, so far asI have been able to ascertain, all the strength ducto fineness. This strength and it: .2 0 II -o bituminous coal, and nine of niter, finely pulverized and thoroughly mixed and moistened by the addition of five per cent. of water, and then dried at about the boiling-point of water, with or without agitation. The bulk will be increased thirty-five per cent. It will be well to first convert the starch in the flour and starch to dextrine by roasting. Again,

one part of sugar, two of bituminous coal,-and

nine of niter. are finely pulverized and-them oughhy mixed. This mixture is then moistcued-with water and dried by a moderate heat The expansion will be from thirty to thirty-five per cent.- Again, one part of sulphur, two of f bituminous coal, and nine of niter, finely pulverized and thoroughly mixed, are heated to about 250 Fahrenheit, to soften the sulphur, and-then'cooled. The expansion will be twentyfiue per cent. From three to' six per eent..ot nitro-glycerine, according to the character of the exploder, mixed with any of these absorbentsycan be detonated with remarkable explosive effect. Of course greater proportions of nitro-glyceriue may be used, it desirable.

I know that rosin, hard tar, sulphur, 850., have-been used as ingredients in absorbents' for nitro glycerine powders, not'only in the hard, dry, and pulverized state, but also in the melted state, being sometimes first melted and then stirred into the other ingredients, and sometimes first mixed with the other-ingredients and 'then'melted and stirred, but-always in su eh abundance as, either by design or ac-' cident,-to conglomerate to a large extent the fine-particles intocoarse grains-that is to say,. many small-particles are cemented solidlyitogether and form-one large grain. The practi cal results of this'arecapacity for detonation vwith a low proportion of nitro glycerine and small explosive force. Ialsoknow that various varnish-like substances have been mixed with pulverized absorbents with like results; also,

that various substances in solution have been mixed with such absorbents; but none of these practices produce my results, and I .do not claim them; but 7 1 w I do claim as my invention and desire to se cure-by Letters Patent-- v 1'. The process of preparing an absorbentt'or a nitro-glyceriue powder by having mingled with the fine particles thereof a small proportion of fusible, solubleyor paste-produciug-inw terial, forming one of the constituents of said mass, and causing such material to melt, dissolve, or become paste while in such mixture,

'sothat each particle of such material becomes an adhesive nucleus to which the surrounding particles attachthemselves, and which, when hardened by cooling, drying, 'or crystallizing, will hold the attached particles together in aggregations, substantially in the manner and for the purposes set forth. I

2. The composition ofinattei or'explosive powderin the form of aggregated grains formed .by the mixtifre of nitr'o-glycerine with said absorbent, whereby detonation is rendered possible with a very low proportion of nit'ro-glycerine, and at the sametime the explosive power derived from theabsorbent is increased.

'rnoMxs VARN'EY;

Witnesses Gino. S. SMALL, a. g

E. L. WATERBURY. 

